When drilling for oil and gas, or other types of wells, a hole is bored into the earth, typically by a drill bit. Drilling mud containing various cuttings fluids are circulated in and out of the well, lubricating the drill bit and carrying away the rock shale, sand, and earth being removed from the bore. The material being removed from the bore is called drill cuttings. While the drilling fluid is necessary to the drilling operation, the shear nature of its formulation makes the mud a contaminant to the environment. Once the contaminated drill cuttings and drill fluid are circulated out of the well, the contaminated fluid and drill cuttings are circulated to a shaker system where the contaminant fluid and drill cuttings pass over a screen on the shakers and other fluid cleaning equipment where the drilling mud and fluids are substantially separated from the drill cuttings.
Drill cuttings contaminated with drilling mud and their various drilling fluids remain a contaminant to the environment and must be handled in an environmentally safe way. Therefore, several inventions have been developed to handle, transport, clean, dry, grind, and/or inject the contaminated drill cuttings and the residual drilling fluids adhering thereto back into the earth formation surrounding the well bore in an efficient and economical manner and in a way that does not restrict or choke the well's drilling production rate. Yet problems still persist that cause production delays due to an inability to process, transport, and dispose of the drill cuttings and economically recover and handle the residual drilling fluid contaminates. These problems are present in virtually all drilling operations.
Cuttings grinding and disposal systems as taught by the prior art have substantially improved the cuttings processing and disposal operations by injecting them back in the earth formation as the well is being drilled. Although vastly improved, such systems are complicated by numerous valves, manifolds, shakers, pumps, adjustable jets, etc., a plurality of tanks and circulatory systems, and further include separate injection skids that require supercharged pumps to expand the earth formations for injection. Although such systems performed the desired function of cuttings injection, several highly trained personnel are required to operate and maintain such systems. These systems have high operating costs, and use considerable deck space. Throughput for these cuttings injection systems have been improved over the years as a result of the addition of more and more sophisticated equipment added to the system to better prepare the cuttings for injection, such as the addition of secondary shakers, and grinding mills. Manifolds and adjustable jets were added to minimize the shutdown times for cleanout of oversize cuttings from the pump units. Improvements to manifolds and valves were made to correct pumps that wore out or plugged quickly.
In short, the cuttings processing and injection systems currently in use are a patchwork of makeshift add-ons used to solve immediate problems in the field.
The cuttings processing and injection system disclosed herein addresses the entire cuttings injection process as a whole and simplifies the process by eliminating choke points, thus improving throughput by improving flow paths, reducing equipment and over-all system size, reducing wear and thus lowering maintenance cost, reducing power consumption, and reducing manpower requirements while improving system reliability.